The present invention relates to the art of trucks and, more particularly, to improvements in dump trucks of the type including an integrated spreader system for conveying material through a tailgate opening while facilitating the hauling of long items or the hauling and/or dumping of material without interference from auxiliary structures carried by the truck for use in conjunction with the integrated spreader system.
Co-pending Application Ser. No. 677,139 filed Jul. 9, 1996, now U.S. Pat. No. 5,890,867 and U.S. Pat. No. 5,823,734 issued Oct. 20, 1998 are incorporated herein by reference to provide background information with respect to one type of vehicle to which the improvements according to the present invention are applicable.
Trucks, such as dump trucks, have been used heretofore to convey materials such as salt, dirt, gravel, and the like for the purposes of spreading such materials onto road surfaces to improve the traction of vehicles traveling thereon during hazardous driving conditions. Dump trucks have also been used to carry and dispense asphalt on road surfaces for repair and maintenance purposes. Materials of the foregoing nature are commonly dispensed from the truck by tilting the dump body so that the materials flow therefrom by gravity and/or by conveying the materials within the dump body out through an opening in the rear wall or tailgate thereof. Dump trucks with such integrated conveyor systems are shown, for example, in U.S. Pat. No. 5,823,734 and in U.S. Pat. Nos. 4,886,214 to Musso, et al. and 5,397,172 to Musso, et al. In this respect, each of these patents discloses a dump truck in which the dump body or material receptacle is provided with an endless conveyor for conveying materials in the dump body to an adjustable feedgate mounted within an opening in the tailgate of the dump body for selective positioning relative to the conveyor to control the dispensing of materials from the dump body. When the truck is not being used to achieve controlled discharge of granular material such as salt, it is desirable that the truck be capable of an alternate use or uses so as to preclude its being idle. Accordingly, the feedgate arrangements in the foregoing patents are mounted on the tailgate of the dump truck and associated therewith such that the tailgate can be opened to provide for the dumping of materials from the dump body by elevating the latter and/or the hauling of elongated objects such as trees, lumber, pipes and the like in a manner which minimizes interference between the materials being hauled and the feedgate apparatus. As will be apparent from the foregoing patents, if the feedgate apparatus is mounted on a tailgate which is pivotal about a horizontal axis at the upper end of the dump body, granular materials and the like in the dump body flowing through the open rear end thereof are likely to have abrasive contact with the feedgate apparatus. Similarly, if the feedgate apparatus is mounted on a tailgate which is pivotal about a horizontal axis at the lower end of the dump body, the feedgate apparatus has to be displaced to a position relative to the tailgate which minimizes contact between long materials being hauled and the feedgate apparatus. Moreover, if the dump truck is to be used for dumping granular materials other than through the use of the feedgate apparatus, it is difficult to position the feedgate apparatus relative to the tailgate so as to preclude abrasive contact of the material being dumped with component parts of the feedgate apparatus. Moreover, the movement of material across the tailgate and the feedgate apparatus results in problems of jamming of the component parts thereof and damage thereto by the abrasive contact of material therewith as well as damage resulting from efforts to move the component parts when they are jammed. All of these problems result in increased maintenance time and cost in connection with clearing jams and/or repairing or replacing damaged component parts.